Dysprosium concentrations

In case of Cu-Dy composites (Table 11.1) dysprosium concentration is higher in sonicated condition in comparison to normal condition, whereas, in case of Mn-Dy... 

In case of crystals of Cu-Dy composite formed under sonication, the concentration of dysprosium increased while in case of the crystals of Mn-Dy and Co-Dy composites, the concentration of dopant, Dy, decreased indicating a strong attraction of Dy for Cu compared to its weak interaction for Mn and Co ions. Nevertheless, the possibility of some of the Dy having been ejected out due to forceful cavitational effect of the ultrasound from the lattice of Mn and Co cannot be ruled out. Higher percentage of Cu, Mn, and Ce in case of Cu-Ce, Co-Ce and Mn-Ce composites, synthesized under sonication compared to normal crystals, could be attributed to the change in the composition of the lattice pattern due to the mechanical impact of ultrasound, whereas, such an effect has not been found in Co salts. These can be seen in Table 11.1. 

Dysprosium was discovered in 1866 by Boisbaudran. It occurs in the earth s crust associated with other rare earth metals. It is found in the minerals, xenotime YPO4, gadolinite, euxemite and monazite (Ce, La, Th)P04. The concentration of dysprosium in seawater is 0.9 ng/L and in the earth s crust 5.2 mg/kg. 

Holmium is obtained from monazite, bastnasite and other rare-earth minerals as a by-product during recovery of dysprosium, thulium and other rare-earth metals. The recovery steps in production of all lanthanide elements are very similar. These involve breaking up ores by treatment with hot concentrated sulfuric acid or by caustic fusion separation of rare-earths by ion-exchange processes conversion to halide salts and reduction of the hahde(s) to metal (See Dysprosium, Gadolinium and Erbium). 

Figure 4. Precipitation of dysprosium from simulated waste as a function of oxalate ion concentration...

Samples (156) were taken from 54 reference lithic pieces that represented five rock types. These samples were analyzed at the SLOWPOKE Reactor Facility of the University of Toronto. They were irradiated for 1 min at 2 kW, or for 1 or 2 min at 5 kW (depending on their radioactivity level in preliminary tests). Upon removal from the reactor, the samples, which weighed between 0.1 and 0.3 g, were left to decay for 18 min and were counted for 5 min with a Ge(Li) y-ray detector coupled to a multichannel analyzer. Trace element concentrations were calculated with the comparator method (7). The 15 elements examined were barium, titanium, sodium, aluminum, potassium, manganese, calcium, uranium, dysprosium, strontium, bromine, vanadium, chlorine, magnesium, and silicon. The first seven of these elements were the most useful in the differentiation of major rock types. 

Gamma rays from spent reactor fuel rods were used for the photoreduction of the trivalent lanthanides. A spectral survey of these divalent containing crystals has been presented by McClure and Kiss (16). This photoreduction technique reduces only a minor fraction of the total trivalent concentration, and those divalent ions produced are unstable with respect to heat and/or light. Fong (3) has described these effects using divalent dysprosium as an example. 

PlOC-3 See The decomposition of nitrous oxide on neodymium oxide, dysprosium oxide and erbium oxide, J. Catal., 28, 428 (1973). Some investigators have reported the rate of this reaction to be independent of oxygen concentration and first-order in nitrous oxide concentration, while others have reported the reaction to be first-order in nitrous oxide concentration and negative one-half-order in oxygen concentration. Can you propose a mechanism that is consistent with both observations ... 

Dysprosium is relatively unreactive at room temperatures. It does not oxidize very rapidly when exposed to the air. It does react with both dilute and concentrated acids, however. For example, it reacts with hydrochloric acid to form dysprosium trichloride. 

The commercially important samarium-containing minerals are treated with concentrated sulfuric acid or, in the case of monazite, with a solution of sodium hydroxide (73%) at approximately 40°C (104°E) and under pressure. The element is separated from the solutions via solvent extraction or ion exchange. Sm salts are weakly yellow and may exhibit ion emission. Sm ions show luminescence and are sometimes used to generate lasers. Samarium is used in the manufacture of headphones and tape drivers, see ALSO Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Lutetium Neodymium Praseodymium Promethium Terbium Ytterbium. 

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